Symmetrical disazo dyestuffs



Patented Sept. 4, 1945 SYlWMETRICAL DISAZO DYESTUFFS Karl F. Conrad and Louis F. Koberlein, Buffalo,

N. Y., assignors to Allied Chemical & Dye Corporation, New York, N. Y., a corporation of New York N Drawing. Application November 19, 1942, Serial No. 4 66,222 9 Claims. (Cl. 260158) This invention relates to direct disazo dyestuffs for cotton. It relates more particularly to new symmetrical disazo-N,N'-diaryl urea type dyestuffs; that is, symmetrical disazo-N,N'-diaryl derivatives of urea and thiourea.

The new azo dyestuffs of this invention comprise symmetrical disazo.-N,N'-diaryl-urea type dyestuffs in which each of the aryl nuclei of the N,N'-diaryl-urea type residue:

is joined to the azo group of a 2-(azo-aryl)- arylenethiazole-disulfonate radical and in which said aryl and arylene radicals are mononuclear. the dyestufifs of this invention comprise symmetrical disazo-N,N-diphenyl ureas and disazo-N,N'-diphenyl thio-ureas in which each of the phenyl nuclei of the N,N'-diphenyl urea type residue is joined to the azo group of a, 2-(azophenyl)-benzothiazoledisulfonate radical, and derivatives thereof in which the phenyl and/or benzo radicals contain one or more substituents in addition to the sulfo groups.

The dyestufis of this invention are orange to dark brown powders, yielding orange to yellow aqueous solutions which dye cotton directly in yellow to orange-red to brown shades possessing exceptional fastness to light and good discharge properties. Their solutions have practically no staining effect on cellulose acetate. Despite the fact that the dyestuffs of this invention contain four solubility-enhancing sulfo groups in the molecule (from which one skilled in the art would expect the fastness to washing to be relatively unsatisfactory), it has been found that the shades produced with the dyestufis of this invention are surprisingly fast to washing.

The dyestuffs of this invention may contain, in the benzene nuclei of the N,N-diphenyl-urea or -thiourea radicals, and in the benzene nuclei of the 2- (azophenyl) -benzothiazole disulfonate radicals, one or more nuclear substituents in addition to the sulfonate groups of the latter radicals. Preferably the substituents are selected from the class consisting of halogen (especially, chlorine or bromine), alkyl and alkoxy groups.

The preferred dyestuffs of this invention are those which are derived from an N,N'-diaryl urea, i. e., a compound of the general formula Preferably, the Z-(azo-aryl) -arylenethiazole disulfonate radicals contain a methyl group in the 6-position, e. g., the dyestuffs are advantageously derived from diazotized dehydro-thio-paratoluidine disulfonate. V

The dyestufi compounds of this invention may be represented in the form of their free acids by the following general formula:

wherein X represents a member of the group consisting of oxygen and sulfur, and the benzene nuclei represented by B1, B2 and B3 maycontain substituents in addition to the indicated sulfonic acid groups.

The dyestuffs of this invention may be prepared, according to one method of procedure, by coupling a' diazotized 2- (amino-aryl) -arylenethiazole-disulfonate, wherein the aryl and arylene radicals are mononuclear, with a substantially equimolecular quantity of a, mononuclear aromatic primary amine (or with an N-substituted derivative thereof in which the substituent is a removable blocking group, e. g., an N-sulfomethyl derivative, if it is necessary to block the amino group during the coupling reaction, followed by elimination of the blocking group after coupling is efiected) and then converting the resulting amino-monazo compound to a disazo-N,N'-diaryl urea by treating the amino-monazo compound with phosgene or other similarly reactive derivative of carbon dioxide, or to a disazo-N,N'-diaryl-thio-urea by treating the amino-monazo compound with thiophosgene, carbon disulfide, or a similarly reactive derivative of carbon disulfide.

In certain cases the order of the said coupling and ureid-iorming operations may be reversed. For example, if an N,N-diphenyl-urea type compound having the formula:

in which the symbols have the above meaning, is susceptible to coupling with a diazotized 2- (amino-aryl) -arylenethiazole disulfonate, the said N,N-oiphenyl-urea type compound may be first prepared (for instance, by phosgenation or thio-phosgenation of the corresponding mononuclear aromatic amine) and then coupled with two molecular equivalents of the diazotized 2- (amino-aryl) -arylenethiazole-disulfonate.

The following examples, in which parts are by weight and temperatures are in degrees centigrade, illustrate the preparation of a number of dyestufis falling within the scope of the invention.

Example 1.-40 parts of dehydro-thio-paratoluidine-disulfonic acid (molecular weight=400), obtained by sulfonating 2-(4'-amino-3'-sulfophenyD-G-methyl benzothiazole, are dissolved in pale yellow powder, which dissolves in water to about 1500 parts of water, and diazotized at 45 form a yellow-orange solution. In the form of by addition of 7 parts of sodium nitrite and 29 thefree acid, it has the following probable forparts of B. hydrochloric acid. Sufficient somula:

H s s CH 3C\ 1 "til r 3 3 32 (H035): dium acetate is added to render the resulting. JiIt' dyes cotton directly from aqueous dye baths solution neutral to Congo red, and 22 part'sof in yellow-orange shades which are extremely fast to light, very fast to washing, and yield good discharges. The dye baths have practically no aniline omega-methane-sodium sulfonatev 9 fl g staining'effect on cellulose acetate. are added in solidform; The resulting mixture Example 2.--28g parts of 'o-anisid'ine-omega is agitated at room temperature for about 16 methane sodium sulfonat aresubstituted for the hours to complete the coupling. Sufiicient 50 per sodium salt of aniline-omega-methane sodium cent aqueous sodium hydroxide solution is then sulfonate employedin Example 1. The procedureadded to render the mixture'faintly alkaline to is otherwise the same. The resulting dyestufl. Nitrazine Yellow paper {neutrality range: pH when ground isan orange powder which dissolves- 6.4 to 6.8), whereupon a sulificient excess of soin water to form-an orange solution. In the form dium hydroxide solution dded to yield a free I of its free acid, it has theprobable formula:

H30 s OOH; 01130 S on: I 0 l i o NV---N.V N (J-N N=N c s c. l a i sodium hydroxide concentration of about 3 per It dyes cotton 'directly'fr'om aqueous dye baths cent. The resultin mixture is boiled forabout brownish-yellow shades which have fastness and two hours to eliminate the omega-sulfo-methyl discharge properties similar to those of the dyeg'roup from the resulting amino-monazo cornst'ufi of'Example 1. I

pound; the mixture is neutralized with hydroxample 3.--15 parts of cresidine (1-methoxychloric acid; the 'amino-monazo compound Z-am'inoA-me'thyhbenzene) are substituted for salted out by addition of sodium chloride, and the aniline omega-methane sodium sulfonate emthe' resultant slurry is'filtered. The product, ob- 40 ployed in the coupling procedure of Example 1. tained as a filter cake} is the sodium salt of -2-(4"- The formed amino-inonazo compound is isolated,

amino-phenyl-4-azo phenyl)-6-methyl benzodissolved. in aqueous sodium carbonate and thiazole disulfonic acid. phosgenated, and the resulting dyestufi is re- The filter cakeis dissolved in about'500 parts covered as described in Example 1. 'The dye'stuff,-

of water; parts of sodium carbonate are added; 45 in dry, ground form, is a light brown powder and a slow current of phosgene is passed-through which dissolves in waterv to form a light brown the solution at room temperature until phosgenasolution. In the form of its free acid, it has the tion is complete. The'disazo-urea compound sepfollowing probable formula:

. J. f. 03 1 $1130". .7 a

a p .H ()JH a,

* scan I. noasg arates from the alkaline solution during phos- It dyes cotton directlyfrom aqueous dye baths genation. (To test for completion of the reaclight brown shades which have good fastness tion, the slurry isspotted on white filter paper properties'and good dischargeability. and streaked with hydrochloric acid. The reac- Eztample 4.-13 parts of para-xylidine are subtion is complete when the spot is a brown-black 'stituted for the cresidine employed in Example 3. precipitate and a faint yellow runout is formed, The procedure is otherwise the same. "The reyielding a brown coloration in the runout anda sulting dyestufi when ground is a deep orange black coloration in the precipitate upon being powder, which dissolves in 'waterto form an streaked with hydrochloric acid.) The slurry is orange brown solution. In the form. of its free then filtered; the filter cake is washed with a two acid, it has the following probable formula:

per cent aqueous solution of commonsaltjand dyescotton directlyimni dyeihaths dried atabout .0.- U J orange-brown shades having gooddischargeabfl- The dyestuffthus obtained when ground isra Z5 ity and fastness properties.

For the preparation of the corresponding thiourea dyestuffs, thio-phosgene or carbon disulfide may :be substituted for the phosgene employed in the above examples and the procedures above described. Further, in the examples and procedures above described, instead of phosgene, its equivalents may be employed; such as, perchlormethyl formate or hexachlor-dimethylcarbonate.

Other variations and modifications of the foregoing examples within the scope of the invention will be apparent to those skilled in the art. Accordingly the examples are to be interpreted in an illustrative rather than in a limiting sense.

In the appended claims, the terms N,N'-diaryl urea type dyestuff and N,N-diaryl urea type (SOaH):

radical," respectively include, generically, N,N'- diaryl urea and -thiourea dyestuffs, and N,N'- diaryl urea and -thiourea radicals.

We claim:

1. A symmetrical disazo N,N'-diaryl urea type dyestufi having a pair of 2-(azo-aryl)-arylenethiazole-disulfonate radicals linked through their azo groups to the aryl radicals of the N,N'-diaryl urea type radical, in which the aryl and arylene radicals are mononuclear.

H o H S iJHl 5. A symmetrical disazo diaryl urea dyestuff having a pair of 2-(azo-aryD-arylenethiazoledisulfonate radicals linked through their azo groups to the aryl radicals of the diaryl urea radical, in which the aryl and arylene radicals are mononuclear.

6. A disazo dyestuif selected from the group consisting of symmetrical disazo diphenyl urea compounds containing a pair of 2-(azophenyD- benzothiazole-disulfonate radicals, linked through their azo groups to the phenyl radicals of the diphenyl urea radical, and their nuclearly substituted halogen, alkyl, and alkoxy derivatives.

'7. A symmetrical disazodiphenyl urea dyestuff having, in the form of its free acid, the following formula:

said dyestufl being, in the form of the sodium salt, a pale yellow solid which dissolves in water to form a yellowish-orange solution and which dyes cotton directly from aqueous dye baths in yellowish-orange shades that are Ifast to light and washing, substantially without staining cellulose acetate.

OCH:

(SOaH):

A symmetrical disazo N,N'-diaryl urea type dyestufi having a pair of Z-(azo-aryl) -6-methylarylenethiazole-disulfonate r a d i c a 1 s linked through theirazo groups to the aryl radicals of the N,N'-diaryl urea type radical, in which the aryl and arylene radicals are mononuclear.

3. A symmetrical disazo N,N'-diaryl urea type dyestufi having a pair of 2-(azo-aryl) -6-methyl- 8. A symmetrical disazo diphenyl urea dyestufi having, in the form of its free acid, the following formula:

CHaO

H 0 I s on,

(not; I

said dyestufi being, in the form of the sodium salt, an orange solid which dissolves in water to form an orange solution and which dyes cotton directly from aqueous dye baths in brownishbenzothiazole-disulfonate radicals linked through having, in the form of its free acid, the followtheir azo groups to the aryl radicals of the N,N'-

OCH:

ing formula:

cmo

diaryl urea type radical, in which the aryl radi- 00 S id dyestufi being, in the form of the sodium cals are mononuclear.

4. A disazo dyestufi selected from the group consisting of symmetrical disazo N,N-diphenyl urea type compounds, containing a pair of 2- (azophenyl)-ibenzothiazole-disulfonate radicals, linked through their azo groups to the phenyl radicals of the N,N-di-phenyl urea type radical, and their nuclearly substituted halogen, alkyl and alkoxy derivatives.

salt, a light :brown solid which dissolves in water to form a light brown solution and which dyes cotton directly from aqueous dye baths in light brown shades that are fast to light and washing.

KARL F. CONRAD. LOUIS F. KOBERLEIN. 

